Mechanical Advantage?

Question

Hey everyone,

I have a little simple machines poster due tommorow and it's really late over here, anyway i need the official formula for getting the Ideal Mechanical Advantage of a wedge. i need the forumla used everywhere (looked at 2 sites and they gave 2 different formulas.

Btw. as in formula I mean like the parenthese part, in example of inclined plane MA, ma=(l/h).

Thanks

Answer 1

The ideal mechanical advantage is related to the frictional force and the force parallel to the surface of the wedge that will push the object.
Fr/Fe = L/h
where Fr is resistance, and Fe is the effort.

In the case of a frictionless surface of the wedge, the resistance is sin(th)*m*g, which is L/h*m*g
The work done by the effort Fe*L is equal to the work done against gravity, m*g*h or Fr*h
therefore, Fr/Fe=L/h

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